Insulating compound.



i E. i

PAEN OFFICE.

JOSEPH F. MENNINGEN, OF WEST ALLIS, WISCONSIN, ASSIGNOR, BY MESNE ASSIGN- MENTS, T0 ALLIS-CHALMERS MANUFACTURING COMPANY, A CORPORATION OF Patented Dec. 1, 1914.

DELAWARE.

INSULATING COMPOUND.

1,119,441, Specification of Letters Patent.

No Drawing. Application filed March 12, 1909.

To all whom it may concern Be it known that I, 'JosnPH F. MENNINGEN, a citizen of the United States, residing at lVest Allis, in the county of Milwaukee and State of lVisconsin, have invented certain new and useful Improvements in Insulating Compounds, of which the following is a full, clear, and exact specification.

This invention-relates to new and useful improvements in insulating compositions and compounds.

The object of the invention is a provision of a compound whichhas excellent insulating properties, which is absolutely fire-proof and impervious to oil or moisture of any kind, and which is particularly hard, strong, and imporous.

The materials or ingredients of my improved insulating compound are sand, hydraulic cement, asbestos and shellac or other substance of a resinous nature possessing like qualities as a binder in the composition; and if desired some coloring matter may be added. The sand will be preferably of very fine grain, and the asbestos may be in either fibrous or in powder form, depending upon the use to which the particular articles are to be put, and to some extent upon the shape of thesame. An suitable hydraulic cement may be employe such as Portland cement, natural cement, Puzzolan cement, or hydraulic lime, but I prefer to use Portland cement.

The proportions by weight of the ingred ents which I have found by careful experiment to produce compounds which answer the requirements very effectively, are substantially as follows :five parts of sand and hydraulic cement, three parts of asbestos and four parts of shellac. The relative proportions of sand and cement may be varied widely, depending largely upon the purpose of the insulating articles to be manufactured and the conditions under which they are to be used. In case a compound of extreme hardness is desired, a greater amount of cement and a less amount of sand will be employed than in a compound wherein extreme hardness is not necessary. The greater the proportion of cement compared with sand, the greater the hardness and imporosity of the compound becomes and the more densely and compactly the molecules are arranged.

In carrying out my invention, the shellac Serial No. 483,047.

having been dissolved in a suitable amount of alcohol to give the proper working conslstency (about equal parts of gum shellac and alcohol have been found satisfactory) the ingredients are thoroughly mixed so as to produce a mixture or composition having substantially the consistency of soft putty. This mixture is then subjected simultaneously to both heat and pressure, this being preferably accomplished by placing the mixture in a hot mold and compressing the same in a suitable press, such as a hand ress. The mixture is then allowed to stun the pressure of the press having been removed, and bake in the mold for a short time, say from one to two minutes, and is then again subjected simultaneously to both heat and pressure in the press, the mold being preferably reheated in order that the mixture may be heated to the proper temperature. This second heating and compressing operation completes the formation of the compound, which is then cooled preferably by being placed in cold water.

The first step of the molding operation, consisting of subjecting the mixture to heat and pressure simultaneously, accomplishes the result, through the applied pressure, of forcing the mixture to the various parts of the mold, and this is no small matter where the molded article is provided with small projections and sharp-angled recesses. This will be appreciated since the consistency of the mixture is only such as is produced by a limited amount of alcohol, the only thinning material employed to bring the composition to a workable consistency. The heat applied to the mixture during this pressing is sufiicient to bring the temperature to a point where the alcohol will be readily evaporated, and, if the article is of small mass, the alcohol may be evaporated even while the pressure is being applied. Ordinarily, however, especially with larger articles, when pressure has been applied to a sufficient degree to cause the mixture to fill the mold, the molded mass is relieved of pressure and allowed to stand while subjected to heat alone, thus effecting, to some extent, a baking of the article. During this period. the alcohol used in obtaining a workable mixture is evaporated. The heat necessary to accomplish the required-"evapm ration may be directly applied to the mold while the same is standing unsubjected to interior in a short while is nevertheless,

pressure, or, as is possible, the heat applied during the first combined pressing and heating operation may be sutiicient, Without any further heat application, to penetrate to the and accomplish the required evaporation. Ordinarily, during this second step of the operation, heat is applied to the mold, but it will be apparent that the feature of this step is allowing heat to act on the molded mass,

BQ rated alcohol cannot escape readily, and may even be sutiicient to cause an explosion of the mold when pressure is applied continuously. After it has been subjected to heat alone for a comparatively short time, the mold is again subjected to both heat and pressure.

This heat and pressure acts to compact the molded mass, which has shrunk perceptibly, due to the evaporation of alcohol, and to completely bake the molded article and render the same close-grained, hard and firm.

It is to be noted that two pressing operations are necessary in most cases, the one to properly fill the mold and to impart the desired shape to the molded article, and the other to thoroughly compact the molded article after the alcohol has been evaporated. It is desirable that the mixture be subjected to heat from the time it is put in the mold, in order to quickly and c5- ciently rid the molded mass of alcohol and to thoroughly bake and harden the molded article.

A compound formed of the materials and proportions above named and in the manner above describedis found to answer all the necessary requirements very effectively and at the same time is easy and inexpensive to manufacture.

What I claim as new and desire to secure by Letters Patent is:

1. An insulating compound consisting essentially of sand, hydraulic cement, asbestos, and a binder comprising a resinous substance.

An insulating compound containing sand, hydraulic cement, asbestos, and a binder of shellac.

3. An insulating compound comprising a mixture of substantially five parts of sand and hydraulic cement, three parts of ashestos, and four parts of shellac.

Milwaukee, Wis, March 5, 1909.

lln testimony whereof I atfix my signature, in the presence of two witnesses.

JOSEPH F. MENNINGEN.

"Witnesses H. C. CASE,

lHAS. lL. BYRON. 

